Thursday, February 7, 2013

While I wrap up the lock-off series that we started months ago, we are going to have a look at an issue that a reader raised a while ago:

Hi Eva,

First of all: thanks for a great blog! Very interesting to read about your research and training tips.I think it would be interesting to hear your thoughts on developing pinch strength. The training of this grip is not too often addressed but in practice I find it is a very important grip type. The strength of the thumb is not developed using the "standard" finger training exercises (dead hangs, campusing etc.). What would you recommend for increasing the strength of the pinch grip?

Thank you! I agree with you. That's why I have been meaning to talk about this topic for some time now ;-)
Firstly, you are so right. There is not a lot of information on this topic and, as you suggest, the hangboard may not be the best method for training this quality... or perhaps it's not so far fetched. Let's see:

How could we train correctly our pinch strength hanging off a vertically oriented pinch?

Well, hanging directly below a board with straight arms like we do for edges and pockets is not the ideal situation. We should hang in a way that left our wrist in a natural position (15º-30º extension, Irmhan, 2001), the forearm in a neutral position (neither supine nor prone) with our thumb pointing 'upwards' (McGorry and Lin, 2007) and our arms in front of us. If we add to this combination an ideal shoulder flexion of 45º-135º, we will be in the best position to apply the maximum force using this grip type (Kong et col., 2011)
The best body posture would be like this:
Or, at least, like this one where the hold is downward facing; our body would be upright, but our elbows would be flexed so that the thumbs could oppose the force made with the other fingers:

By observing a correct position we can avoid injuries like De Quervain syndrome, caused by overuse of thumb muscles under excessive ulnar flexion, exactly the posture that we get when we grab a high, front-facing pinch.

Jason Kehl probably minimizes the risk of injury by way of his great body strength, that allows him to keep a correct elbow and shoulder posture while using an intensity high enough for his hands. Source:http://jasonkehl.dpmblogs.com/

What about diagonal facing pinches?
In this case the drawback is that instead of focusing on the action of the thumb against the other fingers, we would be relying too much on the little finger's friction and the way it is positioned against the hold. As a result, the real contribution of the thumbs to the exercise would be inconsistent, making it difficult to assess the outcome of the training. We would also overload our wrists and little fingers compared to the other fingers.

Hang from down-facing pinches on the underside of the board or use some specialized equipment (like Power Balls, on next picture), assuming that our hands are correctly positioned (palm facing inward, opposed thumb), and our body is in the previously suggested posture. We can achieve this by stepping on footholds on a wall some distance in front of us or, at a more basic level, on the floor:

The most solicited finger in the crimp is the index finger, the middle finger is the one that bears the most load in the open hand and open crimp, and the same goes for the power grip (like grabbing a good rounded tufa) (Quaine et col., 2003; Fuss and Niegl, 2007); in a more 'pure' pinch grip, according to ergonomics studies, apart from the thumb, it is the index finger the one that has the most work at a 35% of the force exerted by the whole hand (Robert et al., 1992). In climbing, the little finger has frequently a key role, not so much because of the force it applies, but rather because of its stabilizing action.

Source: Kapandji (2007)

The pinch is an extraordinarily complex and precise movement, where up to 8 muscles coordinate to allow for several variations of the grip:

Power Grip

Three-jaw chuck pinch

Lateral pinch

Palm pinch

Pulp pinch

The 8 muscles of the thumb

For example, when pinching an arete with all the fingers, the action of the lumbrical and interossei muscles is key for literally 'crushing' it and holding to it. In other kinds of pinches some muscles will have a bigger involvement than others:

- Adductor pollicis: adducts the finger towards the palm (see figure below), and is important when bringing the thumb opposite to the pinky. It is the muscle that works when holding a piece of paper between the thumb and the second metacarpal bone (the index finger's one). Its weakness is the reason why it is difficult to push the thumb against a closed hand, like when we are grabbing a bar
- Abductor pollicis brevis: for wide, shallow pinches
- Opponens pollicis: the one we use to hold firmly an object between the thumb and the fingers, like a pencil; used on good, bar-like tufas
- Flexor pollicis longus: it flexes the distal phalanx, and is used to crimp small and narrow pinches
- Flexor pollicis brevis: helps to oppose the thumb against the smaller fingers and flexes the metacarpophalangeal joint. Important for narrow pinches, especially if they are deep (more than 8cm)
- Abductor pollicis longus: used for 'raising' the thumb
- Extensor pollicis longus: its insertion point is the base of the distal phalange of the thumb. It extends the interphalangeal joint
- Extensor pollicis brevis: insertion point at the base of the proximal phalange. Extends the metacarpal joint. It goes into action in lateral pinches like from the picture above

e) And, of course, including pinches in our training routes or boulder problems, making sure we have access to many different shapes. This will allow us to train the gesture both in a specific way and as part of a real climbing situation:

Vertical or slightly slanted pinches make for a sensational work of general hand strength. This is because we need to firmly oppose the thumb to 'crush' the hold and generate enough friction on all the fingers; in other grip types, the force against the hold surface is usually provided by gravity (apart from finger strength, of course).

If we choose shallow, narrow (less than 5 cm), wide (more than 8cm) or finely textured holds, we will have to focus on making the right amount of pressure and managing the contact surface of the hand.

With this grip type we will improve not only our hand, shoulder or chest strength, but also our feet placement, body position and technique in general. Climbing efficiently on pinches forces us to place our center of mass in a different and more subtle fashion than what is needed for more 'stable' holds like edges and pockets.

Good luck, and enjoy your pinches!

REFERENCES

Cutts A., and Bollen SR (1993). Grip strength and endurance in rock climbers. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 207(2), 87-92.

Interesting post. Thank you for this explanation and for the suggested training exercises. I've always just used a hangboard and noticed that my pinch strength was decent; however, I do occasionally have troubles with my wrist. I'll have to change it up and give these a try. Thanks!

I was skeptical at first, but now I'm convinced that downward-facing holds are the best for training the pinch.

I'm currently training on a rig consisting of: two 12" long pieces of 3" PVC, wrapped with 120-grit sandpaper, that are suspended from the ceiling with length parallel to the ground. They are suspended by a loop of accessory cord through two longitudinally aligned holes dropped in the wall of the pipe, these holes are located are located 1.5" from the ends of the cylinders.

Pulling on these appears to be supremely therapeutic for my wrists. Thank you for your work!

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